There are lots of stainless steel grades, for example: 300 series stainless steel (303, 304/304L, 316/316L, ect), 400 series stainless steel (410, 420, 440C), precipitation hardening stainless steel (PH17-4), and so on. The performance of each grade will be different due to the differences of compositions. Below we list out some popular material grades adopted in stainless steel forging:

304(L) Stainless Steel
304(L) grade is an austenitic stainless steel. It has good corrosion resistance in many environments and may be formed and welded with ease. It has excellent ambient and low temperature toughness properties.
Stainless Steel 304(L) has good inherent forgeability, but its differences from carbon and alloy steels must be taken into account. Type 304 has higher hot strength than carbon, alloy, even martensitic stainless steels, hence much higher forging pressures or more hammer blows are required to forge it – and other austenitic stainless steels. In fact two to three times as much energy is required to forge 300 series stainless steels as is required for carbon and alloy steels.
304 Stainless Steel Forging is widely used in the manufacturing of shafts, valve bodies, valve trim and the food industry.

316(L) Stainless Steel
316(L) stainless steel is the second most common stainless steel grade (after 304 stainless steel) and is commonly used in food and surgical stainless steel applications. The addition of molybdenum prevents specific forms of corrosion. By keeping the carbon below 0.03% max in this austenitic alloy has shown to minimize carbide precipitation during welding. Decreasing the sulfur in this grade will enhance its ability for electro-polishing. 316 SS is also known as marine grade stainless steel due to its increased resistance to chloride corrosion in comparison to 304 SS.
316L stainless steel is an extra low carbon grade of 316 stainless steel; generally used in stainless steel watches and marine applications.
316 stainless steel is widely used in manufacture of manways, pharmaceutical equipment, valve bodies, bleaching and dyeing equipment for the textile industry and the food industry. 316 Stainless steel is resistant to atmospheric corrosion, food products, sterilization solutions and many organic chemicals as well as a variety of inorganic chemicals.